1. Field of the Invention
This invention relates to apparatus for multiple radio frequency communication, and particularly relates to apparatus for using a plurality of radio processing modules to process the signals from various communication channels.
2. Description of the Prior Art
In the traditional beeper or communication system, the receiver of a communication system can only receive the signal in a specific communication channel. When the specific communication channel is occupied by the information from a first source, even though the communication system can process the information from the second source, due to the limitation of the receiver, the communication system can only process the information from the first source. The circuit diagram of the traditional communication system such as a traditional beeper receiving the information from the source is shown in FIG. 1. The demodulator 100 of the traditional communication system receives the radio signal 104 that bearing the information sent by the source 102. The demodulator 100 proceeds with the radio signal 104 to generate the baseband signal 106, thus the frequency of the baseband signal 106 is within the bandwidth of the receiver of the traditional communication system. So only the signal within the bandwidth of the demodulator 100 can be received by the traditional communication system. Because there is only one set of demodulator, the traditional communicational system having only one demodulator is thus named as a single-radio-module communication system. To illustrate the issue resulted from the traditional communication system; the information carried by the signal within the bandwidth of the demodulator 100 is assumed as the first specific information.
The decoding device 108 decodes the baseband signal 106 to generate the digital signal 110, so the specific format used in transmitting the radio signal 106 is converted to a normal format that can be processed by a processor. Then the CPU (central processing unit) 120 processes the digital signal 110 to recreate the message signal that modulated and encoded by the source 102. Because the information is carried by the message signal, thus the information is transmitted from the source to the receiver. The message signal recreated by the CPU 120 is sent to the RAM (random access memory) 125 for storage, and is sent to the displaying device 130 for display.
The issue caused by the traditional communication system mentioned above is the waste of the CPU resource. If the bandwidth of the CPU 120 is larger than the bandwidth of the demodulator 100, and the information occupied the bandwidth of the source 102, then the other information in the other source can not be received by the traditional communication system. The situation mentioned above is caused by the single radio processing module design of the traditional communication system. Due to the bandwidth limitation of the demodulator 100, only the first information transmitted within the bandwidth of the demodulator 100 can be received and processed by the traditional communication system. If there is a second information beyond the range of the bandwidth of the demodulator 100, the second information can not be processed by the traditional communication system. So the single radio processing module design of the traditional communication system wastes the resource of the CPU.